Valves are widely used in fluid systems to provide controlled fluid flow behavior in the systems. Many valves include a conventional cage 10, such as shown in FIG. 1, having a hollow unitary or one-piece body 11 defined by an axial opening 16 extending through opposed ends 12, 14. Flow control openings 18 extend through the sidewall of body 11. With cage 10 positioned inside a valve 20 in a conventional arrangement as shown in FIG. 2, a valve closure unit or plug 22 that is selectably slidably movable in opening 16 controls fluid flow 24 from a valve inlet 26, through flow control openings 18 of cage 10, to a valve outlet 28.
It is noteworthy that fluid flow control requirements for valves are application dependent. For example, the flow control openings 18 of cage 10 of FIG. 1, which may be suitable for use in the above-referenced valve 20 at a first location in a fluid system, may be unsuitable for use in another valve otherwise identical to valve 20 that is positioned at a second location of the fluid system. That is, other than the differently configured flow control openings, which make up a relatively small portion of the respective cages, the remainder of the cages may be identical. As a result, the flow control openings of the cage suitable for use in the valve positioned at the second location would need to be reconfigured, requiring replacement of the cage in its entirety. Additionally, in order for some valves to be adapted for certain applications, such as high temperature applications, the entire cages may need to be composed of a special material or subjected to a treatment, even if only a portion of the cage is subjected to the high temperatures during operation of the valve, resulting in added costs.
What is needed is a valve cage and method for making a valve cage that does not suffer from these drawbacks.